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United States Patent |
5,294,104
|
Nishigaki
|
March 15, 1994
|
Paper feeding device having an adjustable paper feed roller for
different sized sheets
Abstract
A paper feeding device for feeding a sheet of paper from a paper feed
cassette removably mounted in a body of an equipment includes a paper feed
roller, a roller moving member for moving the paper feed roller between a
normal position and a specific position, a fixing member for fixing the
roller moving member so as to hold the specific position of the paper feed
roller upon unloading the paper feed cassette, and a canceling member for
canceling the fixation of the roller moving member by the fixing member so
as to yet hold the specific position of the paper feed roller upon loading
the paper feed cassette again. Accordingly, in the case of continuing to
use the paper of the same size, it is possible to eliminate undue
reciprocation of the paper feed roller between the normal position and the
specific position upon loading and unloading the paper feed cassette and
therefore reduce wear.
Inventors:
|
Nishigaki; Hideo (Nagoya, JP)
|
Assignee:
|
Brother Kogyo Kabushiki Kaisha (Nagoya, JP)
|
Appl. No.:
|
978382 |
Filed:
|
November 18, 1992 |
Foreign Application Priority Data
Current U.S. Class: |
271/117; 271/164 |
Intern'l Class: |
B65H 003/06 |
Field of Search: |
271/117,162,164,171
|
References Cited
U.S. Patent Documents
4098501 | Jul., 1978 | Tani et al. | 271/117.
|
5060927 | Oct., 1991 | Sugiura | 271/117.
|
5106072 | Apr., 1992 | Sugiura et al.
| |
5139252 | Aug., 1992 | Morita et al. | 271/117.
|
Foreign Patent Documents |
607788 | Oct., 1978 | JP.
| |
26619 | Feb., 1991 | JP | 271/117.
|
2225776 | Jun., 1990 | GB.
| |
Primary Examiner: Dayoan; D. Glenn
Assistant Examiner: Mielf; Boris
Attorney, Agent or Firm: Oliff & Berridge
Claims
What is claimed is:
1. A paper feeding device for use with a removable paper feed cassette for
feeding a sheet from the paper feed cassette to equipment, comprising:
a frame and a shaft supported by said frame;
a paper feed roller positionable in a first position and a second position
on said shaft feeding first and second sized sheets respectively from the
paper feed cassette;
a roller moving mechanism movable between a first and second position
coupled to said frame moving said paper feed roller between said first
position and said second position, said roller moving mechanism being in
said first position when said paper feed roller is in said first position;
and
a first elastic biasing member carried on said shaft that normally biases
said paper feed roller into said first position;
a second elastic biasing member coupled to said roller moving mechanism
coupled to said frame to normally bias said roller moving mechanism into
said first position; and
a fixing mechanism coupled to said frame and fixing said roller moving
mechanism in said second position upon removal of the paper feed cassette
from the equipment.
2. The paper feeding device of claim 1, wherein said shaft comprises a
rotatable drive shaft having ends adapted to be coupled to the equipment
and said paper feed roller comprises a pair of rollers supported on said
drive shaft, one of said rollers being fixed to said drive shaft and the
other of said rollers being axially slidable on said drive shaft, and said
first elastic biasing member comprises a compression spring biased between
said fixed roller and said slidable roller to normally bias said other
roller in said first position.
3. The paper feed device of claim 2, wherein said slidable roller is
provided with a one-way clutch to transmit rotation to said slidable
roller in a forward direction
4. The paper feed device of claim 1, wherein said roller moving mechanism
comprises a pivotal lever located adjacent to and in contact with said
paper feed roller and adapted to be supported by the equipment, and said
second elastic biasing member comprises a tension spring contacting said
lever to bias said lever to position said paper feed roller in said first
position.
5. The paper feed device of claim 1, wherein said fixing mechanism
comprises a leaf spring adapted to be mounted to the equipment and
contacting said roller moving mechanism and having an outwardly extending
pawl to engage said roller moving mechanism in said second position.
6. The paper feed device of claim 1 in combination with the paper feed
cassette, further comprising a canceling member for canceling fixing of
said roller moving mechanism by said fixing mechanism.
7. The paper feed device of claim 6, wherein said canceling member
comprises a projection on said cassette which engages with said fixing
mechanism.
8. The paper feed device of claim 6, wherein said fixing mechanism
comprises a leaf spring mounted to a body of a printer contacting said
roller mechanism and having an outwardly extending pawl to engage said
roller moving mechanism in said second position, and said canceling member
disengages said pawl from said roller moving mechanism.
9. The paper feed device of claim 6, wherein said cassette includes a
roller moving chip for engaging said roller moving mechanism to move said
paper feed roller from said first position to said second position.
10. A paper feed assembly, comprising:
a frame body;
a paper feed device mounted in said body, including
a driving shaft rotatably supported by said body,
a paper feed roller means axially movably mounted on said driving shaft and
movable between a first position and a second position,
a first biasing means for normally biasing said paper feed roller means to
said first position,
a roller moving means provided in said body and movable between said first
position and said second position for normally holding said paper feed
roller means in said first position,
a second biasing means for normally biasing said roller moving means to
said first position, and
a fixing means provided in said body for fixing said roller moving means
against the biasing force of said second biasing means to hold said paper
feed roller means in said second position; and
a paper feed cassette means removably mounted in said body, the paper feed
cassette means comprising
a first paper feed cassette for storing a plurality of sheets of paper
having a first size,
a second paper feed cassette for storing a plurality of sheets of paper
having a second size, said first and second paper feed cassettes being
interchangeable in said body,
a canceling member provided in both said first and second paper feed
cassettes, wherein said canceling member cancels fixation of said roller
moving means by said fixing means upon loading one of said first and
second paper feed cassettes into said body, and
a position moving means provided in said first paper feed cassette, for
moving said paper feed roller means from said first position to said
second position against a biasing force of said first biasing means upon
loading said first paper feed cassette into said body to engage said
roller moving means and urge said roller moving means against a biasing
force of said second biasing means,
wherein said fixing means holds said paper feed roller means in said first
position upon unloading said first paper feed cassette from said body.
11. The assembly of claim 10, wherein said paper feed roller means
comprises a pair of rollers supported on said drive shaft, one of said
rollers being fixed to said drive shaft and the other of said rollers
being axially slidable on said drive shaft.
12. The assembly of claim 11, wherein said first biasing means comprises a
compression spring biased between said fixed roller and said slidable
roller to normally bias said slidable roller in said first position.
13. The assembly of claim 10, wherein said roller moving means comprises a
pivotal lever located adjacent to and in contact with said paper feed
roller means and supported by said body, and said second biasing means
comprises a tension spring biased between said lever and said body to bias
said lever to position said paper feed roller means in said first
position.
14. The assembly of claim 10, wherein said fixing means comprises a leaf
spring mounted to said body and contacting said roller moving means and
having an outwardly extending pawl to engage said roller moving means in
said second position.
15. The assembly of claim 10, wherein said canceling member comprises a
projection on said cassette which engages with said fixing means.
16. The assembly of claim 15, wherein said fixing means comprises a leaf
spring mounted to said body contacting said roller moving means and having
an outwardly extending pawl to engage said roller moving means in said
second position, and said canceling member disengages said pawl from said
roller moving means.
17. The assembly of claim 10, wherein said position moving means comprises
a chip on said cassette which engages said roller moving means and pivots
said roller moving means between said first position and said second
position.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper feeding device for feeding a sheet
of paper from a paper feed cassette removably mounted in a body of
equipment such as a copying machine or a printer.
2. Description of Related Art
In such a paper feeding device known in the prior art, a plurality of
sheets of paper having different sizes, such as A4 size and B4 size, are
stored in different paper feed cassettes corresponding to the different
sizes, and the sheets of paper are fed one by one from a desired one of
the paper feed cassettes into the body of the equipment. In the case where
each paper feed cassette has a pair of sheet holding lugs located at the
front corner portions of the cassette, it is common practice to locate a
paper feed roller at a position where an outside end of the paper feed
roller is spaced about 20 mm from a side edge of the sheets of paper.
Accordingly, the position of the paper feed roller for feeding the paper
having the A4 size is different from that for feeding the paper having the
B4 size. In the case where the body of the equipment has a single cassette
loading portion, i.e., a single paper feed opening, it is necessary to
change the position of the paper feed roller according to the chosen paper
size. There are various techniques in the prior art for changing the
position of the paper feed roller according to a paper size.
For example, in a paper feeding device disclosed in U.S. Pat. No.
5,106,072, which is a division of Ser. No. 07/404,904 filed on Sep. 8,
1989 corresponding to United Kingdom Unexamined Patent Publication No. GB
2,225,776 A, and Japanese Patent Publication No. 60-7788, the paper feed
roller is automatically moved to a proper position corresponding to a
paper size and simultaneously set in this proper position when a paper
feed cassette corresponding to this paper size is loaded into the body of
the equipment Further, when the paper feed cassette corresponding to a
specific paper size is unloaded from the body of the equipment, the paper
feed roller is returned to its normal position corresponding to another
paper size.
Another example of a prior art paper feeding device will now be described
with reference to FIGS. 4 and 5. FIG. 4 is a plan view of an essential
part of a prior art paper feeding device 42, and FIG. 5 is a side view of
FIG. 4. Referring to FIGS. 4 and 5, the paper feeding device 42 is of a
type such that a plurality of sheets of paper 32 stored in a paper feed
cassette 31 are offset to the left side (as viewed in FIG. 4) of the paper
feed cassette 31. A driving shaft 33 is rotatably supported at its
opposite ends from the body of a printer. The driving shaft 33 is adapted
to be driven to rotate so as to feed the paper 32 in a direction of arrow
400 shown in FIG. 4. A left feed roller 34a is fixedly mounted on the
driving shaft 33, and a right feed roller 34b is axially slidably mounted
on the driving shaft 33. The right feed roller 34b is provided with a
known one-way clutch 35 so that the rotation of the driving shaft 33 in
the paper feeding direction is transmitted to the right feed roller 34b,
thereby obtaining integral rotation of the driving shaft 33 and the right
feed roller 34b, while the rotation of the driving shaft 33 in the reverse
direction is not transmitted to the right feed roller 34b, thereby
obtaining idling of the driving shaft 33. That is, the right feed roller
34b is rotatable together with the driving shaft 33 through the clutch 35
in the paper feeding direction, and is axially slidable on the driving
shaft 33 in the opposite direction. A compression spring 36 is interposed
between the left feed roller 34a and the right feed roller 34b , so that
the right feed roller 34b is normally biased to the right (as viewed in
FIG. 4) by the compression spring 36. In FIG. 4, the paper 32 of A4 size
is denoted by a one-dot chain line, and a portion of the paper 32 of B4
size exceeding the A4 size paper 32 is denoted by a two-dot chain line.
A roller moving lever 37 is pivotally supported on a shaft 38 mounted on
the body of the printer. A tension spring 39 is provided between the
roller moving lever 37 and the body of the printer to normally bias the
roller moving lever 37 to its normal position shown by a dashed line in
FIG. 4. The right feed roller 34b is normally biased to its normal
position shown by a dashed line in FIG. 4, by the compression spring 36 so
as to deflect the roller moving lever 37. Thus, the roller moving lever 37
and the right feed roller 34b are normally held in the respective normal
positions by the tension spring 39 and the compression spring 36,
respectively.
Further, in the case where the paper feed cassette 31 is an A4 paper
cassette for storing the sheets of paper 32 having the A4 size, the A4
paper cassette is provided with a roller moving chip 40 for moving the
roller moving lever 37 from the normal position to a specific position
shown by a solid line in FIG. 4. That is, when the A4 paper cassette is
loaded into the body of the printer, the roller moving chip 40 is brought
into engagement with a projection 41 of the roller moving lever 37 to urge
the projection 41 to the specific position. In the case where the paper
feed cassette 31 is a B4 paper cassette for storing the sheets of paper 32
having the B4 size, the B4 paper cassette is not provided with the roller
moving chip 40.
The operation of the paper feeding device 42 mentioned above will now be
described. When the B4 paper cassette is loaded into the body of the
printer, the roller moving lever 37 is maintained in its normal position
shown by the dashed line in FIG. 4 because the roller moving chip 40 is
not included in the B-4 paper cassette. Accordingly, the right feed roller
34b is also held in its normal position shown by the dashed line in FIG. 4
by the roller moving lever 37.
In contrast, when the A4 paper cassette is loaded into the body of the
printer, the roller moving lever 37 is urged by the roller moving chip 40
of the A4 paper cassette to move from the normal position shown by (he
dashed line in FIG. 4 to the specific position shown by the solid line in
FIG. 4. Accordingly, the right feed roller 34b is urged by the roller
moving lever 37 to move from the normal position shown by the dashed line
in FIG. 4 to the specific position shown by the solid line in FIG. 4.
When the A4 paper cassette is unloaded from the body of the printer, the
roller moving lever 37 is returned to its normal position by the tension
spring 39. Accordingly, the right feed roller 34b is also returned to its
normal position by the compression spring 36.
However, in such a paper feeding device, paper having the specific size
(e.g., A4 size in the above case) is mostly used, but the paper feed
roller is reciprocated between the normal position and the specific
position whenever the paper feed cassette corresponding to the specific
size is loaded into and unloaded from the body of the equipment in
supplying fresh sheets of paper into the paper feed cassette. Such undue
reciprocation of the paper feed roller causes wearing at a sliding portion
between the paper feed roller and the driving shaft or a pivotal portion
between the roller moving lever and the shaft. Accordingly, there is the
possibility of malfunction such that the paper feed roller cannot be
returned to its normal position because of the worn sliding portion.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a highly
reliable paper feeding device which can move and set the paper feed roller
to a proper position corresponding to a paper size by a simple operation
of loading the paper feed cassette corresponding to the paper size.
It is another object of the present invention to provide a highly reliable
paper feeding device which can eliminate undue reciprocation of the paper
feed roller between the normal position and the specific position upon
loading and unloading the paper feed cassette in the case of continual use
of the same-sized paper.
According to the present invention, a paper feeding device is provided for
feeding a sheet of paper from a paper feed cassette removably mounted in a
body of an equipment. The paper feed cassette comprises a first paper feed
cassette for storing a plurality of sheets of paper having a specific size
and a second paper feed cassette for storing a plurality of sheets of
paper having any size other than the specific size. The first and second
paper feed cassettes are replaceably loaded into the body of the
equipment. The improved paper feeding 15 assembly comprises a driving
shaft rotatably supported at opposite ends thereof to the body of the
equipment; a paper feed roller axially movably mounted on the driving
shaft; first biasing means for normally biasing the paper feed roller to a
normal position thereof; roller holding means provided in the body of the
equipment, for normally holding the paper feed roller at the normal
position; second biasing means for normally biasing the roller holding
means to a normal position thereof; roller moving means provided in the
first paper feed cassette, for moving the paper feed roller from the
normal position to a specific position against a biasing force of the
first biasing means upon loading the first paper feed cassette into the
body of the equipment so as to engage the roller holding means and urge
the roller holding means against a biasing force of the second biasing
means; fixing means provided in the body of the equipment, for fixing the
roller holding means against the biasing force of the second biasing means
to thereby hold the paper feed roller in its normal position upon
unloading the first paper feed cassette from the body of the equipment;
and canceling means provided in both the first and second paper feed
cassettes, for canceling fixation of the roller holding means by the
fixing means upon loading one of the first and second paper feed cassettes
into the body of the equipment.
In operation, when the first paper feed cassette storing the sheets of
paper having the specific size is loaded into the body of the equipment,
the roller holding means provided in the body of the equipment is urged by
the roller moving means provided in the first paper feed cassette. At the
same time, the paper feed roller held in the normal position is moved to
the specific position by the roller holding means. Thereafter, when the
first paper feed cassette is unloaded from the body of the equipment, the
roller holding means is fixed against the biasing force of the second
biasing means by the fixing means provided in the body of the equipment.
Accordingly, 15 the paper feed roller is held in substantially the same
position, that is, in the specific position by he roller holding means.
Thereafter, when the first paper feed cassette is loaded into the body of
the equipment, the fixation of the roller holding means by the fixing
means is canceled by the canceling means provided in the first paper feed
cassette. However, as the roller holding means is urged by the roller
moving means of the first paper feed cassette, the paper feed roller is
held in the specific position by the roller holding means. In contrast,
when the second paper feed cassette storing the sheets of paper having a
size different from the specific size is loaded into the body of the
equipment, the fixation of the roller holding means by the fixing means is
canceled by the canceling means provided in the second paper feed
cassette. In this case, as the second paper feed cassette does not have
the roller moving means, the roller holding means is returned to its
normal position by the biasing force of the second biasing means. At the
same time, the paper feed roller is returned to its normal position by the
biasing force of the first biasing means.
As described above, the paper feed roller can be moved to a proper position
corresponding to a paper size by a simple operation of loading the paper
feed cassette corresponding to the paper size. Further, the paper feeding
device includes the fixing means for fixing the roller holding means
holding the paper feed roller in the specific position and also includes
the canceling means for canceling the fixation of the roller holding means
by the fixing means. Accordingly, in the case of continuing to use the
paper having the specific size, it is possible to eliminate undue
reciprocation of the paper feed roller between the normal position and the
specific position upon loading and unloading the paper feed cassette
storing the paper of the specific size, thereby greatly reducing the
wearing to be caused by the undue reciprocation. Therefore, it is possible
to prevent a malfunction causing the paper feed roller to not be properly
returned to the normal position because of such wearing. Thus, a high
reliability of the paper feeding device can be ensured.
Other objects and features of the invention will be more fully understood
from the following detailed description and appended claims when taken
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional side view of an ink jet printer in a preferred
embodiment according to the present invention;
FIG. 2 is a plan view of an essential part of a paper feeding device in the
preferred embodiment;
FIG. 3 is a side view of FIG. 2;
FIG. 4 is a plan view of a paper feeding device in the prior art; and
FIG. 5 is a side view of FIG. 4.
DESCRIPTION OF PREFERRED EMBODIMENTS
A preferred embodiment of the present invention will now be described with
reference to the drawings.
FIG. 1 shows a general construction of an ink jet printer 1 in the
preferred embodiment according to the present invention. Referring to FIG.
1, a paper feed cassette 3 storing a plurality of sheets of paper 2 is
removably provided in the ink jet printer 1. The sheets of paper 2 are fed
one by one by a paper feed roller 4 from the paper feed cassette 3 to
between a lower feed roller 5 and a nip roller 6. Then, the sheet of paper
2 is fed by the lower feed roller 5 and the nip roller 6 to a printing
section 7. The printing section 7 includes a platen 8 and a printing head
9 disposed opposite to the platen 8.
The printing head 9 is mounted on a carriage 10. The carriage 10 is movably
supported on two guide shafts 11 and 12. The carriage 10 is adapted to be
moved on the two guide shafts 11 and 12 in a direction perpendicular to a
paper feeding direction by driving a carriage motor (not shown). The paper
2 fed to the printing section 7 is brought into close contact with the
platen 8 by a vacuum 15 generated by a suction fan 13. Ink is ejected from
the printing head 9 to the paper 2 on the platen 8, thereby performing a
printing operation. After the printing operation in the printing section
7, the paper 2 is fed by an upper feed roller 14 and a nip roller 15, and
is ejected by a paper ejecting roller 16 to a paper ejecting tray 17.
FIG. 2 is a plan view of an essential part of a paper feeding device 18 in
the preferred embodiment, and FIG. 3 is a side view of FIG. 2. Referring
to FIGS. 2 and 3, the paper feeding device 18 is of a type such that the
sheets of paper 2 stored in the paper feed cassette 3 are offset to a left
side (as viewed in FIG. 2) of the paper feed cassette 3. A driving shaft
19 is rotatably supported at its opposite ends to the body of the printer
1. The driving shaft 19 is adapted to be driven to rotate so as to feed
the paper 2 in a direction of arrow 200 shown in FIG. 2. A left feed
roller 20A is fixedly mounted on the driving shaft 19, and a right feed
roller 20B is axially slidably mounted on the driving shaft 19. The right
feed roller 20B is provided with a known one-way clutch 21 so that the
rotation of the driving shaft 19 in the paper feeding direction is
transmitted to the right feed roller 20B, thereby obtaining integral
rotation of the driving shaft 19 and the right feed roller 20B, while the
rotation of the driving shaft 19 in the reverse direction is not
transmitted to the right feed roller 20B, thereby obtaining idling of the
driving shaft 19. That is, the right feed roller 20B is rotatable together
with the driving shaft 19 through the clutch 21 in the paper feeding
direction, and is axially slidable on the driving shaft 19 in the opposite
direction. A compression spring 22 as the first biasing means according to
the present invention is interposed between the left feed roller 20A and
the right feed roller 20B, so that the right feed roller 20B is normally
biased to the right (as viewed in FIG. 2) by the compression spring 22. In
FIG. 2, the paper 2 of an A4 size is denoted by a one-dot chain line, and
a portion of the paper 2 of a B4 size exceeding the A4 size paper 2 is
denoted by a two-dot chain line.
A roller moving lever 23 as the roller holding means according to the
present invention is pivotally supported to a shaft 24 mounted on the body
of the printer 1. A tension spring 25 as the second biasing means
according to the present invention is provided between the roller moving
lever 23 and the body of the printer 1 to normally bias the roller moving
lever 23 to its normal position shown by a dashed line in FIG. 2. The
right feed roller 20B is normally biased to its normal position, shown by
a dashed line in FIG. 2, by the compression spring 22 so as to urge the
roller moving lever 23. Thus, the roller moving lever 23 and the right
feed roller 20B are normally held in the respective normal positions by
the tension spring 25 and the compression spring 22, respectively.
A leaf spring 27 is mounted at one end thereof to the body of the printer 1
so as to resiliently overlap the roller moving lever 23. The leaf spring
27 is provided with a downwardly projecting pawl 26 as the fixing means
according to the present invention. The pawl 26 is adapted to engage the
roller moving lever 23. That is, when the roller moving lever 23 is moved
to its specific position shown by a solid line in FIG. 2, and is
thereafter to be returned to the normal position by the tension spring 25,
the pawl 26 comes into engagement with the roller moving lever 23 to stop
the return movement of the roller moving lever 23 to the normal position.
The paper feed cassette 3 is provided with a canceling member 28 as the
canceling means according to the present invention, for canceling the
engagement of the pawl 26 of the leaf spring 27 with the roller moving
lever 23. That is, when the paper feed cassette 3 is loaded into the body
of the printer 1 in the condition where the pawl 26 is in engagement with
the roller moving lever 23, the leaf spring 27 is forcibly lifted by the
canceling member 28 to thereby disengage the pawl 26 from the roller
moving lever 23 as shown in FIG. 3.
Further, in the case where the paper feed cassette 3 is an A4 paper
cassette for storing the sheets of paper 2 having the A4 size, the A4
paper cassette is provided with a roller moving chip 29 as the roller
moving means according to the present invention, for moving the roller
moving lever 23 from the normal position to the specific position. That
is, when the A4 paper cassette is loaded into the body of the printer 1,
the roller moving chip 29 is brought into engagement with a projection 30
of the roller moving lever 23 to urge the projection 30 to the specific
position. In the case where the paper feed cassette 3 is a B4 paper
cassette for storing the sheets of paper 2 having the B4 size, the B4
paper cassette is not provided with the roller moving chip 29. Further,
both the A4 paper cassette and the B4 paper cassette have the canceling
member 28.
The operation of the paper feeding device 18 mentioned above will now be
described. When the B4 paper cassette is loaded into the body Of he
printer 1, the roller moving lever 23 is maintained in its normal position
shown by the dashed line in FIG. 2 because the roller moving chip 29 is
not included in the B4 paper cassette. Accordingly, the right feed roller
20B is also held in its normal position shown by the dashed line in FIG. 2
by the roller moving lever 23.
In contrast, when the A4 paper cassette is loaded into the body of the
printer 1, the roller moving lever 23 is urged by the roller moving chip
29 of the A4 paper cassette to move from the normal position shown by the
dashed line in FIG. 2 to the specific position shown by the solid line in
FIG. 2. Accordingly, the right feed roller 20B is urged by the roller
moving lever 23 to move from the normal position shown by the dashed line
in FIG. 2 to the specific position shown by the solid line in FIG. 2.
When the A4 paper cassette is unloaded from the body of the printer 1, the
roller moving lever 23 is 15 inclined to be returned to its normal
position by the tension spring 25. However, the pawl 26 of the leaf spring
27 comes into engagement with the roller moving lever 23 to stop the
return movement of the roller moving lever 23. Accordingly, the right feed
roller 20B is held in substantially the same position, that is, in its
specific position by the roller moving lever 23.
Thereafter, when the A4 paper cassette is loaded again into the body of the
printer 1, the leaf spring 27 is lifted by the canceling member 28 of the
A4 paper cassette to cancel the engagement of the pawl 26 of the leaf
spring 27 with the roller moving lever 23. However, as the specific
position of the roller moving lever 23 is held by the roller moving chip
29 of the A4 paper cassette, the right feed roller 20B hardly moves to
hold its specific position.
In contrast, when the B4 paper cassette is loaded into the body of the
printer 1 after unloading the A4 paper cassette, the leaf spring 27 is
lifted by the canceling member 28 of the B4 paper cassette to cancel the
engagement of the pawl 26 of the leaf spring 27 with the roller moving
lever 23. In this case, since the B4 paper cassette does not have the
roller moving chip 29, the roller moving lever 23 is returned to its
normal position by the tension spring 25. Accordingly, at the same time,
the right feed roller 20B is also returned to its normal position by the
compression spring 22.
As described above, in the paper feeding device 18 in the above preferred
embodiment, the right feed roller 20B can be moved to a proper position
corresponding to a size of the paper 2 and set in this proper position by
a simple operation of loading the paper feed cassette 3 corresponding to
the size of the paper 2. Further, the paper feeding device 18 includes the
leaf spring 27 having the pawl 26 for fixing the roller moving lever 23
and also includes the canceling member 28 for canceling the fixation of
the roller moving lever 23 by the pawl 26 Accordingly, in the case of
continuing to use the paper 2 having the A4 size, it is possible to
eliminate undue reciprocation of the right feed roller 20B between the
normal position and the specific position upon loading and unloading the
A4 paper cassette, thereby greatly reducing the wearing at a sliding
portion between the right feed roller 20B and the driving shaft 19 and at
a pivotal portion between the roller moving lever 23 and the shaft 24.
Therefore, it is possible to prevent a malfunction due to such wear
wherein the right feed roller 20B cannot be properly returned to the
normal position.
While the invention has been described with reference to a specific
embodiment, the description is illustrative and is not to be construed as
limiting the scope of the invention. Various modifications and changes may
occur to those skilled in the art without departing from the spirit and
scope of the invention as defined by the appended claims.
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